A substantial problem with external mirrors, particularly in the case of commercial vehicles, is the occurrence of vibration. First, vibration can negatively affect the use of the mirror, and second, vibration of the mirror can lead to damage due to fatigue.
An attempt at a solution to this problem is disclosed in German Patent Publication No. DE-A-40 10 083. In the mirror construction there given, the housing does not exert any carrying function. This carrying function was taken over by means of a holding apparatus onto which a securing means for the affixing of the mirror on a commercial vehicle is fastened. The housing, and at least one mirror pane of the external mirror and an adjustment unit for the positioning of the mirror, are affixed to the holding apparatus. The disadvantage of this is that the carrier plate and the holding apparatus are of separate construction, leading to the danger that the stability of securement of the carrier plate in the holder is reduced. This is especially the case when—as shown in an embodiment of DE-A-40 10 083—the housing is clamped between the holding apparatus and the carrier plate, since here, vibrations can be transferred easily to the carrier plate.
Another external mirror for a motor vehicle is made known by U.S. Pat. No. 4,701,037, wherein a holding arm running to the body and a single piece carrier plate with a molded-on clamp bearing is provided. Where this is concerned, a mirror position adjustment unit is involved onto which a mirror carrier plate is mounted with its mirror pane.
Finally, European Patent Publication No. EP-A-0 590 510 brings into common knowledge an external mirror for commercial vehicles, which exhibits a holder for connection to the body of the vehicle, a carrier plate disposed in a housing, upon which a housing is held and on which, by means of a fastening device the holder is secured, at least one pivotable mirror assembly with a mirror pane is fastened to the carrier plate, and at least one adjustment unit, which is affixed to the carrier plate and is at least bound to the pivoting of said mirror assembly. Experience has shown that even with this mirror design, in actual use, the vibrations are still very large. This is true especially where installation in a truck is involved.